Animal life is plentiful and varied within the park. Large mammals include mule deer, black bears, coyotes, mountain lions (pumas), and the endemic and endangered Sierra Nevada bighorn sheep (Ovis canadensis sierrae). Various squirrels, chipmunks, and bats constitute most of the smaller mammals, which also include the rare and endangered Pacific fisher (Martes pennati pacifica). More than 250 species of birds have been observed in the park, of which some 165 species reside there or visit regularly and the others are seen there only occasionally. Among the more common birds found are Steller’s jays, western meadowlarks, and mountain bluebirds. In addition, there are populations of amphibians (including salamanders, toads, and frogs), lizards (notably western pond turtles), and fish (especially trout).

Development and use of the park

Yosemite Valley, east-central California, U.S..; photograph by Carleton E. Watkins, 1860–61.Library of Congress, Washington, D.C.Trappers may have entered Yosemite Valley in the 1830s, and a miner named William Penn Abrams reportedly reached Inspiration Point (near the valley entrance) in 1849. The valley certainly became known to the world after a California state militia force pursued marauding Native Americans into it in 1851. Settlers soon followed, including entrepreneurs who set up lodgings for visitors who arrived there by horseback or on foot over rough steep trails. Interest in Yosemite was spurred by the dissemination of lithographs of drawings and paintings by artists such as Thomas Hill and of photographs by Carleton E. Watkins. Concerns about the degradation of the natural environment from this influx of people prompted calls for the federal government to protect Yosemite Valley and the Mariposa Grove, which it did by authorizing the establishment of a state park there in 1864.

Map of Yosemite Valley (c. 1900), Yosemite National Park, east-central California, U.S., from the 10th edition of Encyclopædia Britannica.Encyclopædia Britannica, Inc.U.S. Pres. Theodore Roosevelt and naturalist John Muir at Glacier Point, Yosemite Valley, California, U.S.Encyclopædia Britannica, Inc.Wagon roads were completed to the park’s northern and southern boundaries in the mid-1870s, and by 1885 some 3,000 visitors were reaching the park annually. In 1890—largely through the efforts of naturalist John Muir and writer and magazine editor Robert Underwood Johnson—the U.S. Congress set aside land around the state park as Yosemite National Park. Muir continued to urge the federal government to acquire all of the parkland, and, at his invitation, Pres. Theodore Roosevelt visited him at Yosemite in 1903. Finally, in 1906, the state park land was merged into the national park. Other parcels of land were subsequently added until the park reached its present size. A railroad was completed to the west end of the park in 1907 (discontinued in 1945), and the number of visitors rose dramatically, surpassing 15,000 in 1914 and more than double that number the following year. Annual attendance passed a half million in 1940 and, after a lull during World War II, reached one million for the first time in 1954.

Reproduction of a semisubterranean Miwok dwelling, Yosemite Museum, Yosemite National Park, east-central California, U.S.UrbanHiking is popular along Yosemite’s hundreds of miles of trails, and thousands of climbers scale the domes and peaks annually. The Pacific Crest National Scenic Trail cuts across the northeastern portion of the park; before exiting in the east, it is joined by the John Muir Trail, the northern terminus of which is at the head of Yosemite Valley. Rafting is permitted on portions of the Merced River. The Badger Pass Ski Area, to the south of the valley, is a winter recreation centre. There are two visitor’s centres: a year-round one in Yosemite Valley and another, open seasonally, in the eastern part of the park near the Tioga Pass entrance. The Yosemite Museum, in Yosemite Village in the valley, contains exhibits on the area’s native Miwok and Paiute peoples.